An effective and selective route to 1,5-dihydropolyalkylated s-indacenes: Characterization of their mono- and dianions by silylation. Structure of trans-1,5-bis(trimethylsilyl)-2,6-diethyl-4,8-dimethyl-s-indacene

Dahrouch, MR; Jara P.; Mendez, L.; Portilla, Y; Abril, D.; Alfonso, G.; Chavez, I; Manriquez, JM; Riviere-Baudet, M; Riviere, P; Castel A; Rouzaud, J; Gornitzka, H

Abstract

2,5-Dimethyl-1,4-bis(carboxyalkyl)benzenes were prepared in almost quantitative yield by alkylation of malonic esters from 2,5-dimethyl-1,4-dibromomethylbenzene obtained by bromomethylation of 1,4-dimethylbenzene. The methyl groups on the central benzene ring induce intramolecular, regiospecific cycloeliminations leading selectively to the diketones, the precursors of the corresponding 1,5-dihydro-s-indacenes, which also were obtained in very high yield. These new ligand precursors were easily converted to the mono- or dianions, which were characterized by means of the mono- or disilylated compounds. Disilylation occurs in cis and trans position. The structure of the trans-1,5-bis(trimethylsilyl)-2,6-diethyl-4,8-dimethyl-s-indacene was obtained by X-ray diffraction. Hexaalkyl-1,5-dihydro-s-indacenes underwent regioselective monosilylation and regiospecific and stereoselective disilylation. Disilylation of the less hindered tetraalkyl-1,5-dihydro-s-indacenes was regioselective and stereoselective.

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Título según WOS: An effective and selective route to 1,5-dihydropolyalkylated s-indacenes: Characterization of their mono- and dianions by silylation. Structure of trans-1,5-bis(trimethylsilyl)-2,6-diethyl-4,8-dimethyl-s-indacene
Título según SCOPUS: An effective and selective route to 1,5-dihydropolyalkylated s-indacenes: Characterization of their mono- and dianions by silylation. Structure of trans-1,5-bis(trimethylsilyl)-2,6-diethyl-4,8-dimethyl-s-indacene
Título de la Revista: ORGANOMETALLICS
Volumen: 20
Número: 26
Editorial: AMER CHEMICAL SOC
Fecha de publicación: 2001
Página de inicio: 5591
Página final: 5597
Idioma: English
URL: http://pubs.acs.org/doi/abs/10.1021/om010119w
DOI:

10.1021/om010119w

Notas: ISI, SCOPUS